This invention pertains to the art of fluid fittings and, more particularly, to fluid couplings.
The invention is particularly applicable to a dielectric tube coupling in which it is imperative that electrical conduction through the coupling be impaired, and will be described with particular reference thereto. However, it will be appreciated by those skilled in the art that the invention has broader applications and uses. One such alternative use, for example, would be in the prevention of galvanic corrosion as may occur when a union between two dissimilar metals is required.
It is often necessary or desirable to connect or couple electrically conductive fluid lines or tubes while concurrently restricting electrical conduction through the coupling itself. Applications for a dielectric coupling ar oftentimes present for isolating fluid lines used to transport flammable media.
Another application for a dielectric coupling resides in the prevention of galvanic corrosion, such as occurs when two dissimilar metals are brought into electrical contact. Galvanic corrosion may occur, for example, if copper tubing such as is typically used to transport water is brought into electrical contact with a steel tank of the type used in many water vessels.
Prior dielectric couplings have generally included the use of sleeves, O-rings, non-conducting washers, or combinations thereof in a manner where a fluid seal is at least partially effected by a dielectric material. These materials are typically subjected to longitudinal compression which may cause buckling, or to compressinal forces which may cause the material to crumble or crack. Prior art fittings can lose a seal of internal media when the dielectric material loses compression as may occur by repeated opening or tightening of the coupling. Limitations in the dielectric material itself may further place limits on the line pressure which may be maintained.
The present invention contemplates a new and improved dielectric coupling which overcomes all of the above-referred problems and others, and provides a simple and more reliable dielectric coupling arrangement.